Remove spurious backticks detected by `rustdoc::unescaped_backticks`

Remove spurious backticks detected by `rustdoc::unescaped_backticks` · model-checking/verify-rust-std@c8db8ea

Original file line number	Diff line number	Diff line change
`@@ -786,7 +786,7 @@ where`
`786`	`786`	`///`
`787`	`787`	`/// The caller must also ensure that the memory the pointer (non-transitively) points to is never`
`788`	`788`	/// written to (except inside an `UnsafeCell`) using this pointer or any pointer derived from it. If
`789`		-/// you need to mutate the pointee, use [`from_mut`]`. Specifically, to turn a mutable reference `m:
	`789`	+/// you need to mutate the pointee, use [`from_mut`]. Specifically, to turn a mutable reference `m:
`790`	`790`	/// &mut T` into `*const T`, prefer `from_mut(m).cast_const()` to obtain a pointer that can later be
`791`	`791`	`/// used for mutation.`
`792`	`792`	`///`